Background

Assessing general skeletal muscle function

Skeletal muscle strength is of great interest to a wide range of people. It is commonly used by people wishing to improve their fitness, as a goal for athletes, and to assess decline in clinical and aging populations. This is a wide range of applications, and as such there are a wide range of tests that can be performed. This lab will cover three different assessments: skeletal muscle endurance, strength, and static (isometric) strength.

Skeletal muscle strength can be measured by isometric, isokinetic, or isotonic testing. Some populations, such as unfit older adults or other groups at a high risk of injury, are often tested with isometric exercises. Athletic and young, healthy populations are typically tested with isotonic exercises. As with aerobic endurance testing, muscular strength testing can be a maximal effort, or a submaximal test that will estimate maximal strength.  For this lab, we will assess skeletal muscle endurance and strength with isotonic and isometric tests.

Class activity

Activity 1: Upper body skeletal muscle strength and endurance (push-up test)

Push-up tests are a simple method for testing skeletal muscle strength and endurance in healthy individuals. This test requires little equipment and space, and can be conducted as either a one-on-one test or as a field test. However, it is not well-suited for all age ranges or people with shoulder injuries.

Equipment: Workout mat

Participant: Each person (who is cleared for activity and does not have shoulder concerns) will participate in the activity

Additional reading: Your textbook figure 4.4 has additional instructions and pictures. Use this table to interpret the results (note: be sure to use the knees table for women): https://www.topendsports.com/testing/tests/home-pushup.htm

Instructions: (abbreviated from your textbook)

Notes: only count complete push-ups in the correct form

1. Start in the push-up “down” position. Men: start in the standard push-up position. Women: start on knees, with lower legs on the floor and feet planter flexed and laying on top of the mat
2. Raise the body by straightening the elbows to just before they lock, then return to the starting “down” position. This is one repetition.
3. Continue with good technique (back straight, arms fully extended) until the participant is unable to maintain the correct technique for two repetitions. After the first incorrect push-up technique, give a warning to the participant. Although this is not a cadence test, if the participant requires a rest of more than ~3 seconds between repetitions the test can be terminated for excessive rest.
4. Compare your results with the table in the link above.

Activity 2: YMCA bench press skeletal muscle endurance test

At least one person per group will complete this test (ideally, everyone). This test uses an absolute weight for the strength assessment, based on identity of man or woman (non-binary can use whichever weight they are more comfortable lifting, but unfortunately there is not a norms table for comparison).

Equipment: Bench press set, spotter

Participant: At least one person per group who is cleared for strength testing will complete this test. If you have shoulder concerns, please have someone else from your group be the participant.

Instructions:

1. Men will lift 36kg and women 16kg.
2. Count how many repetitions can be safely completed.
3. Compare your results to the table in Blackboard.

Activity 4: Wall sit

Equipment: Wall, timer

Participant: Everyone cleared for lower body testing.

Instructions:

1. Find a wall that you can easily rest against at a 90 degree angle (you may wish to go into the hallway outside the lab).
2. Sit against the wall, with knees at 90 degrees and feet in line with knees.
3. Time how long you can sit against the wall, without breaking form.
4. Compare your results (in seconds) to the table posted in Blackboard.

Activity 5: Static leg strength

Equipment: Goniometer, static strength platform

Participant: Everyone cleared for weight training will participate. If you have a knee, ankle, or back concern please use your best judgement and talk to an instructor if you are unsure. A partner is needed to check the joint angle prior to the start of the test.

Instructions:

1. Have the participant stand on the platform in a partial squat while holding the hand bar across their thighs. Using a goniometer, confirm that the participant‘s knees are flexed at an angle between 130-140° and adjust the length of the chain as needed.
2. After a brief post-setup rest, the participant holds the hand bar with a pronated grip and rests the bar across their thighs.
3. Using only the legs (not the back), slowly extend the knees and exert as much force as possible.
4. The participant will do two attempts with a one minute rest in between. Record the highest attempt.
5. Convert to kg and use table in the Blackboard folder for this lab to look up strength classification (use “leg strength” column for this test).

Bonus activity: plank hold

Equipment: Padded exercise mat, timer

Participant: Everyone cleared for exercise testing.

Instructions:

1. Place exercise mat on the floor.
2. Get into a plank position (on elbows and feet) and start timer.
3. Compare your time, in minutes, to the table posted in Blackboard.